Techniques for performing remote management of computers are well known in the art. Remote management generally refers to the operational control of a given computer by another, remotely located computer. Examples of such control include, but are not limited to, configuring software, re-boot operations, status determination of field-replaceable units (FRUs), diagnostic procedures, firmware downloading, keyboard/video/mouse redirections, configuring the operating system, etc. Some management commands are of value when the computer being managed does not have a fully functioning operating system installed that would typically provide the mechanisms for managing the computer. This requires specialized mechanisms for controlling the computer that don't require the operating system to be fully functioning.
In many systems, computers to be managed are coupled via local area networks (LANs), serial data links or modems to a managing entity, such as a remotely located management terminal (e.g., another computer). Point-to-point links, such as so-called RS-232 serial links, are typically dedicated for this purpose and are therefore subject to more direct control by an operator of the system thereby allowing physical security to be implemented and making logical security less of a concern. However, RS-232 serial connections are limited in distance and to point-to-point connections. Additionally, these point-to-point links typically exist apart from the network connections used to convey other types of traffic between the computer being managed and other computers. Other forms of networked communication, such as LAN, wide area networks (WAN) and IEEE 1394 (absent the teachings of the present invention), allow greater distance connectivity choices but require complicated logical security and cannot support general communication simultaneously, requiring additional special purpose communication hardware.
Such techniques are further limited. For example, while it is possible using these techniques for the remote computer to access key components including memory and memory-mapped devices (i.e., memory accessed by software, such as operating systems, memory mapped hardware devices to be managed and service processors) of the computer being controlled, the process is generally very difficult requiring complex and non-standardized hardware. Generally, in such systems, the computer's processor must act as an intermediary between the component under consideration and a remote management entity, thereby diminishing the reliability of management commands. However, other types of communication links are capable of providing such direct access to key computer components. For example, the IEEE 1394 serial bus allows a remote computer to directly access internal computer components without the intervention of the computer's processor. Furthermore, this remote access does not prevent general communication on the 1394 serial bus, which requires simultaneous use of the computer's processor. For this reason, the IEEE 1394 serial bus represents an attractive option for use in remote computer management. (The IEEE 1394 serial bus standard is based largely upon the internationally adopted ISO/IEC 13213 (ANSI/IEEE 1212) CSR Architecture Specification and the IEEE 1394-1995 Serial Bus Specification.)
Although technologies that allow more direct access to a computer's components, such as IEEE 1394 serial bus technology, can be used to advance remote computer management techniques, such techniques do raise security concerns. That is, any communication link that provides a remote management terminal access to a given computer's components may also be exploited by other devices to gain access. For example, it may be possible for any device coupled to the IEEE 1394 serial bus to similarly gain access to a given computer's internal components. Similar security concerns arise with other networking technologies, such as “ETHERNET” networks. These security holes represent a significant impediment to the use of such technology in the area of remote computer management. Thus, a technique that overcomes such security concerns in the context of remote computer management would represent advancement in the art.